Archos 50c Oxygen AC2000A2 Replacement Battery 3.7V 2000mAh

Archos 50c Oxygen — 3.7V Li-Polymer Replacement Battery (AC2000A2)

This is a 3.7V, 2000mAh Li-Polymer replacement battery for the Archos 50c Oxygen smartphone. It slots in where the original AC2000A2 cell sits, restoring power to the display, processor, and cellular radio. Dimensions are 76.20 × 58.10 × 3.70mm — confirm these against your existing cell before fitting.

• Archos 50c Oxygen fit: The 50c Oxygen uses a flat Li-Polymer pouch cell on a 3.7V nominal rail. This cell matches the original connector pinout and BMS communication protocol, so the phone's charge IC recognises it without an adapter or modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the 50c Oxygen platform. The BMS handshake completed correctly, charge termination triggered at the expected 4.2V ceiling, and protection cutoff activated at the low-voltage threshold without fault flags.
• First-cycle fuel gauge reset: On first use after installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC pushes higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Archos 50c Oxygen

This is a voltage cliff issue, not a capacity fault. When the modem transmits or the screen brightness spikes, instantaneous current draw pulls the cell voltage below the BMS cutoff threshold — even if the reported percentage looks safe. A fresh cell with an uncalibrated fuel gauge IC makes this worse because the coulomb counter is still reading from the old discharge curve. Run one full discharge-charge cycle without interruption and the IC recalibrates. If shutdowns persist after two full cycles, measure resting cell voltage — it should read 3.7V or above at the 30% reported level.

Phone not powering on after the replacement cell sat in storage

Li-Polymer cells self-discharge in storage, and if the voltage drops below approximately 2.5V per cell, the BMS enters a lockout state to prevent damage. The phone will show nothing — no charge indicator, no boot — when you first connect it. Connect the phone to a wall adapter and leave it for 15–20 minutes before attempting to power on. The charge IC delivers a trickle current at low voltage to bring the cell back above the BMS re-enable threshold, typically around 3.0V, before switching to normal charge current.